1. Field of the Invention
The present invention generally relates to a method and an apparatus for supplying electric components (e.g., electronic components) and an apparatus for mounting electric components, and particularly to the art of improving the efficiency of supplying of electric components.
2. Related Art Statement
U.S. Pat. No. 5,695,309 discloses an electric-component (xe2x80x9cECxe2x80x9d) supplying apparatus including a plurality of EC supplying units each of which feeds a carrier tape carrying a plurality of electric components (xe2x80x9cECsxe2x80x9d) and thereby supplies the ECs, one by one, and each one of which is selectively positioned at an EC-supply position to supply one or more ECs. The carrier tape carries the ECs at a predetermined EC-carry pitch and, when a driven member of each EC supplying unit is driven, the carrier tape is fed at a predetermined tape-feed pitch by a carrier-tape feeding device of the unit, so that the ECs are positioned, one by one, at an EC-supply portion of the unit. The plurality of EC supplying units are provided on a movable table such that the respective EC-supply portions of the units are arranged along a straight line, and the movable table is movable in a direction parallel to the straight line, so that each one of the units is selectively positioned at the EC-supply position. A drive member which drives the driven member of each EC supplying unit is provided in the vicinity of the EC-supply position. The plurality of EC supplying units share the drive member and a drive device which drives the drive member. The present EC supplying apparatus can supply the carrier tapes at a lower cost than an apparatus wherein a plurality of EC supplying units include respective drive members and drive devices.
In the above-indicated EC supplying apparatus, the moving of the EC supplying units occurs at a timing different from that at which the feeding of the carrier tape on each EC supplying unit does. For example, after the movable table is moved and the EC-supply portion of one of the EC supplying units is positioned at the EC-supply position, one EC is taken from the carrier tape supplied by the one EC supplying unit, and the drive member is engaged with the driven member of the one unit to feed the carrier tape. After the feeding of the carrier tape, the movable table is moved so that the EC-supply portion of another EC supplying unit is positioned at the EC-supply position.
However, recently, there has been a demand to shorten a positioning time which is needed to position the EC-supply portion of each EC supplying unit at the EC-supply position. For example, the EC supplying apparatus may be employed in an EC mounting system to supply ECs to an EC mounting apparatus of the system. The EC mounting apparatus includes an intermittent-rotation body which intermittently rotates about a vertical axis line at a predetermined rotation-angle pitch, and a plurality of EC holders which is provided on the rotation body such that the EC holders are equiangularly spaced from each other about the vertical axis line at a predetermined spacing-angle pitch equal to the rotation-angle pitch. As the rotation body is intermittently rotated, the EC holders are sequentially moved to each of stop positions including an EC-receive position where each of the EC holders receives an EC from the EC supplying apparatus, and an EC-mount position where each EC holder mounts the EC on a circuit substrate as an example of an object on which ECs are to be mounted. In this case, a cyclic operation time is defined as a time duration needed for an EC holder following another EC holder to reach a stop position after that another EC holder reaches that stop position. Japanese Patent Application laid open for public inspection under Publication No. 6(1994)-342998 discloses an EC mounting apparatus wherein the moving of EC holders by the rotation of an intermittent-rotation body occurs partially concurrently with the EC taking and mounting actions of each of the EC holders, so as to shorten the cyclic operation time of the apparatus. To this end, it is required that the EC-supply portion of each of the EC supplying units be moved to the EC-supply position at a shorter time interval. Accordingly, both a time duration which can be used to position the EC-supply portion of each EC supplying unit at the EC-supply position, and a time duration which can be used to feed the carrier tape on each EC supplying unit are shortened. However, in the case where the acceleration and deceleration of movement of the movable table is increased to shorten the positioning time, the vibration which is produced when the movement of the movable table is started and stopped is increased, which leads to lowering the accuracy of positioning of the EC-supply portion of each EC supplying unit at the EC-supply position. On the other hand, in the case where the acceleration and deceleration of feeding of the carrier tape is increased to shorten the time duration needed to feed the carrier tape, the life expectancy of each EC supplying unit is reduced because the inertia of the unit is great and a great load is applied to the constituent members of the unit (e.g., the members of the carrier-tape feeding device).
In the case where the moving of the EC supplying units and the feeding of each carrier tape are concurrently carried out, the time interval at which the EC-supply portion of each EC supplying unit reaches the EC-supply position can be shortened without having to shorten the time duration needed to position the EC-supply portion of each EC supplying unit at the EC-supply position or the time duration needed to feed the carrier tape.
It is therefore an object of the present invention to provide an electric-component supplying method which improves the efficiency of supplying of electric components by shortening a time interval at which respective component-supply portions of component-supply units reach a component-supply position, without having to shorten a time duration which can be used to position the component-supply portion of each component-supply unit at the component-supply position, or a time duration which can be used to feed a carrier tape on each component-supply unit.
It is another object of the present invention to provide an electric-component supplying apparatus which enjoys the same advantage of the above method.
It is another object of the present invention to provide an electric-component mounting apparatus which enjoys the same advantage of the above method.
The present invention provides an electric-component supplying method, an electric-component supplying apparatus, and an electric-component mounting apparatus which have one or more of the technical features that are described below in respective paragraphs given parenthesized sequential numbers (1) to (13). Any technical feature which includes another technical feature shall do so by referring, at the beginning, to the parenthesized sequential number given to that technical feature. Thus, two or more of the following technical features may be combined, if appropriate. Each technical feature may be accompanied by a supplemental explanation, as needed. However, the following technical features and the combinations thereof are just the examples to which the present invention is by no means limited.
(1) According to a first feature of the present invention there is provided a method of supplying a plurality of electric components, with an electric-component supplying apparatus comprising a component-supply table including a displaceable table which is displaceable in a reference direction, and a plurality of component-supply units which are provided on the displaceable table such that respective component-supply portions of the units are arranged along a line parallel to the reference direction, each of the component-supply units including a driven member and a carrier-tape feeding device which feeds, based on the driven member being driven, a carrier tape carrying the electric components at a predetermined component-carry pitch, at a tape-feed pitch equal to a quotient obtained by dividing the component-carry pitch by an integral number, so that the electric components are positioned, one by one, at the component-supply portion of the each unit, a table displacing device which displaces the displaceable table and thereby positions the component-supply portion of the each component-supply unit, at a predetermined component-supply position, at least one drive member which is provided near the component-supply position, and at least one drive device which drives the drive member which in turn drives the driven member of the each component-supply unit, the method comprising the step of causing the drive member to drive the driven member of the each component-supply unit being displaced with the displaceable table, while causing the drive member to follow the driven member being displaced, so that at least a portion of at least one of a carrier-tape feeding operation and a tape-feed preparing operation of the carrier-tape feeding device of the each unit is performed while the each unit is displaced with the displaceable table. The line parallel to the reference direction may be a straight line, a circle, a circular arc, a curve other than the circular arc, or a combination of two or more of those lines. In the case where the line is a straight line, the displaceable table is provided by a linearly displaceable table; in the case where the line is a circle, the displaceable table is provided by a circular (full-circular) table which is rotatable about an axis line; and in the case where the line is a circular arc, the displaceable table is provided by a sectorial (part-circular) table which is rotatable about an axis line. Each of the circular table and the sectorial table can be said as a rotary table which is rotatable about an axis line. The carrier tape may be one which includes an accommodating tape having, at a predetermined pocket pitch, a plurality of pockets accommodating a plurality of electric components (xe2x80x9cECsxe2x80x9d), respectively, and a cover tape fixed to the accommodating tape to close respective openings of the pockets; or one which carries ECs having lead wires and which includes a pair of holding tapes which extend parallel to each other and hold the lead wires of the ECs. Each of the component-supply units may be one which includes a carrier-tape feeding device and a carrier-tape storing device; or one which includes a carrier-tape feeding device but does not include a carrier-tape storing device. The latter component-supply units are disclosed in U.S. patent application Ser. No. 09/099,460 assigned to the Assignee of the present application. The patent application also discloses a plurality of stationary carrier-tape storing devices which correspond to the respective carrier-tape feeding devices of the component-supply units, respectively. Thus, when the displaceable table is displaced, the component-supply units are displaced, so that the respective carrier-tape feeding devices thereof are displaced relative to the stationary carrier-tape storing devices. In the present EC supplying method, the component-supply table is displaced by the table displacing device so that the component-supply portion of each of the component-supply units is positioned at the component-supply position, and the drive member is driven by the drive device to drive the driven member and thereby feed the carrier tape. The drive member drives the driven member while being displaced with the driven member being displaced with the displaceable table. Thus, while the component-supply units are displaced with the displaceable table, at least a portion of at least one of the carrier-tape feeding operation and the tape-feed preparing operation occurs. Thus, even in the case where a time pitch at which the respective component-supply portions of the plurality of component-supply units reach the component-supply position is limited to a short time, the component-supply portion of each component-supply unit can be positioned at the component-supply position while the carrier tape is fed on the each unit, without having to shorten a time duration needed to displace the displaceable table or a time duration needed to feed the carrier tape. That is, the component-supply portion of each component-supply unit can be positioned at the component-supply position at a short time interval, while the carrier tape is fed on the each unit, without having to increase the acceleration and deceleration of displacement of the displaceable table or increase the acceleration and deceleration of feeding of the carrier tape. Therefore, the efficiency of supplying of the ECs can be improved without lowering the accuracy of supplying of the ECs or reducing the life expectancy of the component-supply units. In the case where the carrier-tape feeding device of each component-supply unit performs both the carrier-tape feeding operation and the tape-feed preparing operation, at least a portion of either one, or each, of the two operations may be performed while the component-supply units are displaced. In the case where the carrier-tape feeding device performs only the carrier-tape feeding operation, at least a portion of the carry-tape feeding operation is performed while the component-supply units are displaced. In this connection, it is noted that the present EC supplying method may be combined with any one of the second to twelfth features (2) to (12), described below, of the EC supplying apparatus of the present invention.
(2) According to a second feature of the present invention there is provided an electric-component supplying apparatus comprising a component-supply table including a displaceable table which is displaceable in a reference direction, and a plurality of component-supply units which are provided on the displaceable table such that respective component-supply portions of the units are arranged along a line parallel to the reference direction, each of the component-supply units including a driven member and a carrier-tape feeding device which feeds, based on the driven member being driven, a carrier tape carrying a plurality of electric components at a predetermined component-carry pitch, at a tape-feed pitch equal to a quotient obtained by dividing the component-carry pitch by an integral number, so that the electric components are positioned, one by one, at the component-supply portion of the each unit; a table displacing device which displaces the displaceable table and thereby positions the component-supply portion of the each component-supply unit, at a predetermined component-supply position; at least one drive member which is provided near the component-supply position; at least one drive device which drives the drive member which in turn drives the driven member of the each component-supply unit; at least one drive-member returning device which permits, in a state in which the drive member is engaged with the driven member of the each component-supply unit being displaced with the displaceable table, the drive member to be displaced with the driven member being displaced and, in a state in which the drive member is away from the driven member, returns the drive member to a reference position thereof. In the present EC supplying apparatus, when the displaceable table is displaced and the component-supply units are displaced, the drive member is moved with the driven member of each component-supply unit being displaced, while being engaged with the driven member. Thus, at least a portion of at least one of the carrier-tape feeding operation and the tape-feed preparing operation is performed while the component-supply units are displaced. The movement of the drive member with the driven member is permitted by the drive-member returning device. In the state in which the drive member is away from the driven member after having driven the driven member, the returning device returns the drive member to its reference position where the drive member can engage the driven member of another component-supply unit. The reference position may be a position aligned with the component-supply position as seen in the reference direction, or a position away upstream or downstream from the component-supply position as seen in the reference direction. The present EC supplying apparatus enjoys the same advantages of the EC supplying method according to the first feature (1) of the present invention.
(3) According to a third feature of the present invention that includes the second feature (2), the drive-member returning device comprises a drive-member holder which holds the drive member such that the drive member is movable in a direction intersecting the reference direction; a guide device which guides the drive-member holder in a direction parallel to the reference direction; and a biasing device which biases the drive-member holder toward the reference position of the drive member. The drive member drives the drive member so that the drive member is moved in a direction intersecting the reference direction so as to be engaged, and disengaged from, the driven member. In the state in which the drive member is engaged with the driven member, the drive member is displaced with the driven member being displaced, and the drive-member holder is also displaced with the drive member being displaced with the driven member. In the state in which the drive member is away from the driven member, the biasing device biases the drive-member holder so that the holder is displaced in a direction opposite to the direction in which the holder is displaced with the drive member being displaced with the driven member, so that the drive member and the drive-member holder are returned to the reference position of the drive member.
(4) According to a fourth feature of the present invention that includes the third feature (3), the biasing device comprises a pair of biasing members which apply, to the drive-member holder, respective elastic forces in opposite directions, so that the drive-member holder is allowed to move in each of the opposite directions. The displaceable table is displaced in the reference direction parallel to the line along which the respective component-supply portions of the component-supply units are arranged, so that the respective component-supply portions of the units may be sequentially positioned at the component-supply position where each of the units supplies one or more ECs. The displaceable table may be displaced in such a manner that after all the component-supply units that are pre-selected from all the units on the displaceable table to supply ECs in one EC-supplying operation have finished supplying the ECs, the displaceable table is returned, at a stroke, to its supply-start position where the next EC-supplying operation is to be started. Otherwise, the displaceable table may be displaced in such a manner that the pre-selected component-supply units supply ECs not only while the displaceable table is displaced forward but also while the table is displaced backward. In the latter case, both while the displaceable table is displaced forward and while the table is displaced backward, the respective component-supply portions of the pre-selected units are sequentially positioned at the component-supply position where each of the units supplies one or more ECs. The order of the sorts of the ECs supplied during the backward displacement of the table is reverse to that of the sorts of the ECs supplied during the forward displacement of the table. Moreover, the displaceable table may be displaced such that the table is alternately displaced forward and backward two or more times in one EC-supplying operation. Furthermore, the displaceable table may be displaced in such a manner that while it is taken as a general rule that the pre-selected units supply ECs only while the table is displaced forward, the table is allowed to displace backward only in special cases, such as when one unit fails to supply one or more ECs, so that another unit which has finished supplying one or more ECs can supply one or more ECs in place of the one unit. In the present EC supplying apparatus, the pair of biasing members apply, to the drive-member holder, respective biasing forces in opposite directions, so that the drive-member holder is allowed to move in each of the opposite directions. Therefore, even if the displaceable table may be displaced forward and backward for supplying ECs, the drive member can be moved with the driven member of each of the component-supply units, so that the carrier tape can be fed while the units are displaced with the displaceable table.
(5) According to a fifth feature of the present invention that includes the fourth feature (4), the drive-member returning device further comprises a pair of movable members which are biased toward respective stop positions by the pair of biasing members, and wherein a slight space is left between the drive-member holder and each of the pair of movable members that is positioned at the stop position thereof. Each of the two movable members cannot be moved over the stop position thereof, but can be moved, against the biasing force of a corresponding one of the two biasing members, in a direction opposite to the direction in which the each movable member is biased by the one biasing member. Therefore, when the drive member being engaged with the driven member is displaced with the driven member, one of the two movable members that is biased by one biasing member against the biasing force of which the drive-member holder is moved, is moved with the drive-member holder, and the other movable member is held at the stop position thereof. In the state in which the drive member is away from the driven member, the one movable member is moved toward the stop position thereof against the biasing force of the one biasing member, so that the drive-member holder is returned to the reference position of the drive member in a direction opposite to the direction in which the drive member engaged with the drive member is moved with the driven member. After the one movable member is moved to its stop position, the drive-member holder is held at the reference position. In the present EC supplying apparatus, the drive-member holder can be stopped at the reference position more quickly and accurately than in the case where the holder is stopped at the reference position by the balance of the respective biasing forces of the two biasing members. That is, the drive member can be more quickly prepared for engaging the driven member of another component-supply unit.
(6) According to a sixth feature of the present invention that includes the fifth feature (5), the drive-member returning device further comprises an engageable member which is different from the drive member and which is supported by the drive-member holder such that the engageable member is movable to an engaging position where the engageable member engages an engageable portion of the each component-supply unit and to a retracted position where the engageable member does not engage the engageable portion; and an engageable-member moving device which moves the engageable member to each of the engaging position and the retracted position. Usually, the engageable member is positioned at its retracted position. However, when the drive member is engaged with the driven member of one component-supply unit, the engageable member is moved to its engaging position where the engageable member engages the one unit. Thus, the drive member is forced to displace with the driven member because of the engagement of the engageable member and the one unit and the connection of the engageable member and the drive-member holder. Since the drive member is stably engaged with the driven member, the drive member can surely drive the driven member while being displaced with the driven member. The engageable member may be one which is formed as an integral portion of the drive member held by the drive-member holder, or one which is directly supported by the drive-member holder, independent of the drive member.
(7) According to a seventh feature of the present invention that includes any one of the second to sixth features (2) to (6), the drive-member returning device comprises a drive-member holder which holds the drive member such that the drive member is movable in a direction intersecting the reference direction; a guide device which guides the drive-member holder in a direction parallel to the reference direction; a detector which is provided on the drive-member holder and which detects a detectable portion of the each component-supply unit; and a holder moving device which includes a drive source and which moves the drive-member holder such that the detector continues to detect the detectable portion of the each component-supply unit. The detector may be one of various known switches or sensors, such as a limit switch, a proximity switch, a transmission-type or reflection type photoelectric sensor. The detectable portion of each component-supply unit may be provided depending upon the specific sort of the detector. The drive source may be provided by a compliance which is electrically controllable, such as an electric motor. Based on an output from the detector which is detecting the detectable portion, the drive-member holder is forced to move with each component-supply unit. Since the drive member is stably engaged with the driven member, the displacement of each unit and the feeding of the carrier tape on each unit surely occur concurrently with each other.
(8) According to an eighth feature of the present invention that includes any one of the second to seventh features (2) to (7), the electric-component supplying apparatus comprises two drive members and two drive-member returning devices which return the two drive members to respective reference positions thereof, the two drive members alternately driving the respective driven members of the component-supply units. Since the present EC supplying apparatus includes the two drive members and the two driven-member returning devices, the two drive members may be alternately engaged with the respective driven members of the component-supply units whose component-supply portions are sequentially positioned at the component-supply position. In this case, the two drive members alternately drive the respective driven members of the units. Therefore, it is possible to increase a cyclic operation time during which each drive member is displaced with the driven member from the reference position of each drive member and is returned to the reference position. For example, in the EC supplying apparatus according to the above-indicated third feature (3) wherein the drive-member holder is returned to the reference position by the biasing device, the biasing device may be one which has a small biasing force only. In this case, each drive member can be surely moved with the driven member. On the other hand, if the biasing device is one which has a great biasing force, a great resistance is produced when each drive member is displaced with the driven member and the drive-member holder is moved against the biasing force of the biasing device. In this case, the displacement of each drive member with the driven member may be obstructed. If the present EC supplying apparatus employs the biasing devices each of which has a small biasing force, only a small resistance is produced, which permits each of the drive members to be surely moved with the driven member. The guide device which guides the drive-member holder may be one which includes a guided member provided with a rolling member such as a ball, and a guide member which is engaged with the guided member via the rolling member and which guides the guided member. In this case, the resistance produced when the drive-member holder is moved is further reduced, so that the holder can be more lightly moved and accordingly the drive member can be more reliably moved with the driven member.
(9) According to a ninth feature of the present invention that includes any one of the second to eighth features (2) to (8), the drive device comprises a first drive device including a first drive source, and a second drive device including a second drive source independent of the first drive source. In the present EC supplying apparatus, the carrier tape can be fed based on the drive member being driven by each of the first and second drive devices. Whether the first or second drive device is operated may depend on the specific sort of the carrier tape to be fed, and/or the conditions of their peripheral devices. Both the first and second drive devices may be used for feeding the same sort of carrier tape under the same conditions of their peripheral devices.
(10) According to a tenth feature of the present invention that includes the ninth feature (9), the first drive device further comprises a cam mechanism including a rotary cam which is rotated by the electric motor, and a cam follower which follows the rotary cam, and the second drive source comprises a fluid-pressure-operated cylinder device. In the first drive device, the timings at which the drive member is engaged with, and disengaged from, the driven member, and the velocity at which the drive member is moved are defined by the shape of the rotary cam. In the second drive device, the fluid-pressure-operated cylinder device can drive the drive member a desired number of times at respective desired timings. The rotary cam of the cam mechanism of the first drive device may be so shaped as to be able to use, as the drive source thereof, the electric motor which is also used as a drive source of another device, while assuring that the drive member is engaged with, and disengaged from, the driven member at desired timings. Otherwise, the rotary cam may be so shaped as to be able to start and stop the movement of the drive member without producing vibration.
(11) According to an eleventh feature of the present invention that includes any one of the second to tenth features (2) to (10), the drive device comprises a rotary cam; a cam follower which follows the rotary cam; a fluid-pressure-operated actuator including an operative portion which is movable in a first direction in which the operative portion presses the cam follower against the rotary cam, and in a second direction in which the operative portion moves the cam follower away from the rotary cam; a valve device which changes a direction in which a working fluid is supplied to the fluid-pressure-operated actuator and thereby switches the movement of the operative portion to one of the first and second directions. The valve device may be one which includes a single solenoid-operated valve, or one which includes a plurality of shut-off valves. In the state in which the cam follower is pressed against the rotary cam, the cam follower follows the rotary cam, so that the drive member is engaged with, and disengaged from, the driven member. In the case where the drive member is not used to drive the driven member for some reason, the fluid-pressure-operated actuator is switched to the second direction, so that while the rotary cam continues to rotate, the cam follower does not follow the rotary cam and the drive member does not drive the driven member. That is, the rotation of the rotary cam may not be transmitted to the drive member, without having to stop the rotation of the electric motor. For example, in the case where the drive device shares, with another device, an electric motor as a drive source which drives the rotary cam, the drive member can be prevented from driving the driven member, without having to stop the operation of the another device that involves the operation of the electric motor. The fluid-pressure-operated actuator functions as not only a following-causing device which causes the cam follower to follow the rotary cam but also a stopping device which stops the cam follower from following the rotary cam.
(12) According to a twelfth feature of the present invention that includes any one of the second to eleventh features (2) to (11), the driven member includes a flat driven portion parallel to the reference direction, and the drive member includes a flat drive portion which is perpendicular to the reference direction and the flat driven portion. The flat drive and driven portions can be easily produced, and the drive portion can be surely engaged with the flat driven portion because the flat driven portion has a great area.
(13) According to a thirteenth feature of the present invention, there is provided an electric-component mounting apparatus comprising a component-supply table including a displaceable table which is displaceable in a reference direction, and a plurality of component-supply units which are provided on the displaceable table such that respective component-supply portions of the units are arranged along a line parallel to the reference direction, each of the component-supply units including a driven member and a carrier-tape feeding device which feeds, based on the driven member being driven, a carrier tape carrying a plurality of electric components at a predetermined component-carry pitch, at a tape-feed pitch equal to a quotient obtained by dividing the component-carry pitch by an integral number, so that the electric components are positioned, one by one, at the component-supply portion of the each unit; a table displacing device which displaces the displaceable table and thereby positions the component-supply portion of the each component-supply unit, at a predetermined component-supply position; a circuit-substrate holding device which holds a circuit substrate on which electric components are to be mounted; a plurality of component holders which hold respective electric components; a holder revolving device which revolves the component holders about an axis line perpendicular to the reference direction, and sequentially positions the component holders at a component-receive position opposed to the component-supply position; a component-reception control device which controls the holder revolving device and each of the component holders such that the each component holder receives, while being positioned at the component-receive position, an electric component from the component-supply portion of the each component-supply unit being positioned at the component-supply position; a component-mounting control device which controls the holder revolving device and the each component holder such that the each component holder mounts, while being opposed to the circuit substrate held by the circuit-substrate holding device, the electric component on the circuit substrate; at least one drive member which is provided near the component-supply position; at least one drive device which drives the drive member which in turn drives the driven member of the each component-supply unit; at least one drive-member returning device which permits, in a state in which the drive member is engaged with the driven member of the each component-supply unit being displaced with the displaceable table, the drive member to be displaced with the driven member being displaced and, in a state in which the drive member is away from the driven member, returns the drive member to a reference position thereof. Each of the component holders may be one which holds an EC by applying a negative pressure (or a vacuum) thereto, or one which includes a plurality of grasping members which can be opened and closed to hold an EC. The holder revolving device may be one which includes an intermittent-rotation body which is intermittently rotatable about an axis line, and a drive device which intermittently rotates the body. In this case, the plurality of component holders may be provided on the intermittent-rotation body such that the holders are equiangularly spaced from each other about the axis line at a predetermined spacing-angle pitch equal to a predetermined rotation-angle pitch at which the body is intermittently rotated about the axis line. As the body is intermittently rotated, the holders are sequentially moved to the component-receive position and a component-mount position where each of the holders mounts an EC on the circuit substrate. The axis line about which the body is intermittently rotated may be a vertical axis line or an axis line inclined with respect to a vertical plane. The plurality of component holders may be mounted on a rotatable body which is rotatable about an axis line by any desired angle in each of opposite directions. In this case, the rotatable body may be mounted on a movable device such as an X-Y robot, so that each of the holders mounted on the rotatable body may be moved to any desired position based on the movement of the movable device and may receive or mount an EC at the desired position based on the rotation of the body. The holder revolving device may be one which includes a plurality of rotary members which are rotatable about a common axis line, independent of each other, and a rotary-motion applying device which applies a rotary motion to each of the rotary members such that the each rotary member is fully rotated about the common axis line, is stopped at least one time during the full rotation thereof, and has a predetermined time difference from the preceding or following rotary member. In this case, the plurality of component holders may be supported by the plurality of rotary members, respectively. In an EC mounting apparatus which employs the above-indicated holder revolving device including the plurality of rotary members, or in the EC mounting apparatus which is disclosed in the previously-identified Japanese document No. 6-342998, the cyclic operation time of each of the component holders is shortened for the purpose of improving the efficiency of mounting of ECs. In addition, according to the present feature (13), the displacement of each component-supply unit and the feeding of the carrier tape on the each unit concurrently occur. This feature greatly contributes to improving the efficiency of mounting of ECs. The present EC mounting apparatus may be combined with any one of the above-indicated features (2) to (12) of the EC supplying apparatus.